数据库存图片和文件，客户端浏览图片或下载文件

数据库存图片和文件，客户端浏览图片或下载文件（通过Model层，多层应用）

1、数据库：

CREATE TABLE [TArticle] (
[Pkid] [int] IDENTITY (1, 1) NOT NULL ,
[ArticleTitle] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[AttachmentFile] [image] NULL ,
[FileExtName] [varchar] (12) COLLATE Chinese_PRC_CI_AS NULL ,
CONSTRAINT [PK_tArticle] PRIMARY KEY  CLUSTERED
(
[Pkid]
)  ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

2、模型层：

using System;
using System.Collections.Generic;
using System.Web;

namespace WebSqlImageFile.bol
{
public class Article
{
public Article(){ }

private int _pkid;
private string _articletitle;
private byte[] _attachmentfile;
private string _fileextname;

public int Pkid
{
set { _pkid = value; }
get { return _pkid; }
}

public string ArticleTitle
{
set { _articletitle = value; }
get { return _articletitle; }
}

public byte[] AttachmentFile
{
set { _attachmentfile = value; }
get { return _attachmentfile; }
}

public string FileExtName
{
set { _fileextname = value; }
get { return _fileextname; }
}
}
}

3、DAL层：

using System;
using System.Collections.Generic;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using WebSqlImageFile.bol;
using System.IO;

namespace WebSqlImageFile.dal
{
public class ArticleDal
{
const string connection_string = @"Data Source=.;Initial Catalog=NorthwindCN;Integrated Security=True";

public List<bol.Article> GetList()
{
List<bol.Article> list = new List<bol.Article>();
string sql = "SELECT [Pkid], [ArticleTitle], [AttachmentFile], [FileExtName] FROM [TArticle]";
using (SqlConnection objConn = new SqlConnection(connection_string))
{
objConn.Open();
SqlCommand objCmd = new SqlCommand(sql,objConn);
SqlDataReader objReader = objCmd.ExecuteReader();
while (objReader.Read())
{
bol.Article bo = new Article();
bo.Pkid = objReader.GetInt32(0);
bo.ArticleTitle = objReader.GetString(1);

//字节数组读取(数据库字段类型为image类型)
bo.AttachmentFile = (byte[])objReader.GetValue(2); //GetValue

bo.FileExtName = objReader.GetString(3);
list.Add(bo);
}
if (!objReader.IsClosed) objReader.Close();
objConn.Close();
}
return list;
}

public bol.Article GetBo(int pkid)
{
bol.Article bo = null;
string sql = "SELECT [Pkid], [ArticleTitle], [AttachmentFile], [FileExtName] FROM [TArticle] WHERE Pkid=" + pkid.ToString();
using (SqlConnection objConn = new SqlConnection(connection_string))
{
objConn.Open();
SqlCommand objCmd = new SqlCommand(sql, objConn);
SqlDataReader objReader = objCmd.ExecuteReader();
if (objReader.Read())
{
bo = new Article();
bo.Pkid = objReader.GetInt32(0);
bo.ArticleTitle = objReader.GetString(1);

//字节数组读取(数据库字段类型为image类型)
bo.AttachmentFile = (byte[])objReader.GetValue(2);

bo.FileExtName = objReader.GetString(3);
}
if (!objReader.IsClosed) objReader.Close();
objConn.Close();
}
return bo;
}

public bool Insert(bol.Article bo,out int pkid)
{
bool is_ok = false;
pkid = 0;
string sql = @"INSERT INTO [TArticle]([ArticleTitle], [AttachmentFile], [FileExtName]) VALUES(@ArticleTitle,@AttachmentFile,@FileExtName) ";
sql += " ;select @@identity; ";

List<SqlParameter> paras = new List<SqlParameter>();
paras.Add(new SqlParameter("@ArticleTitle", bo.ArticleTitle));

//byte数组写入(数据库字段类型为image类型)
SqlParameter para_AttachmentFile = new SqlParameter("@AttachmentFile", SqlDbType.Image); //参数类型为Image
para_AttachmentFile.Value = bo.AttachmentFile;
paras.Add(para_AttachmentFile);

paras.Add(new SqlParameter("@FileExtName", bo.FileExtName));

using (SqlConnection objConn = new SqlConnection(connection_string))
{
objConn.Open();
SqlCommand objCmd = new SqlCommand(sql, objConn);
objCmd.Parameters.AddRange(paras.ToArray());
object objPkid = objCmd.ExecuteScalar();
if (objPkid != null)
if (Int32.TryParse(objPkid.ToString(), out pkid)) { is_ok = true; }
objConn.Close();
}
return is_ok;
}
//
}
}

4、BLL业务逻辑层（省略）

5、界面层

（1）、添加：

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using WebSqlImageFile.bol;
using WebSqlImageFile.dal;

namespace WebSqlImageFile
{
public partial class Upload : System.Web.UI.Page
{
protected void btnSubmit_Click(object sender, EventArgs e)
{
//取值
string title = txtTitle.Text=txtTitle.Text.Trim();
HttpPostedFile upload_file = fileUpload.PostedFile;

//判断
if (title != string.Empty && upload_file != null && upload_file.ContentLength > 0)
{
bol.Article bo = new Article();

//bo.Pkid=

bo.ArticleTitle = title;

//bo.AttachmentFile
int len = upload_file.ContentLength;                         //读上传文件,上传文件字节大小
bo.AttachmentFile = new byte[len];                           //读上传文件,初始化一个byte数组,长度为上传文件字节大小
upload_file.InputStream.Read(bo.AttachmentFile, 0, len);     //读上传文件,上传文件.输入流.读(字节数组,从0开始,长度为文件大小)

//bo.FileExtName=
string[] ss = upload_file.FileName.Split(new char[]{'//'});
string file_name = ss[ss.Length - 1];//文件名
string[] ss2 = file_name.Split(new char[] { '.' });
if (ss2.Length > 1)
bo.FileExtName = ss2[ss2.Length - 1];
else
bo.FileExtName = ""; //没有扩展名

//保存
int pkid = 0;
bool b = new dal.ArticleDal().Insert(bo,out pkid);
if (b)
{
//lblInfo.Text = string.Format("提交成功,内码:{0}.",pkid);
//txtTitle.Text = "";
Response.Redirect("Show.aspx?id=" + pkid.ToString(),false);
}
}
else
{
lblInfo.Text = "资料不完善!";
}
}
//
}
}

（2）、BLOB输出页面：（图片显示或文件下载）

去除aspx文件中的所有HTML代码，只留一行声明行

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="AttachF.aspx.cs" Inherits="WebSqlImageFile.AttachF" %>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

namespace WebSqlImageFile
{
public partial class AttachF : System.Web.UI.Page
{
private int pkid = 0;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Request["id"] != null)
{
if (Int32.TryParse(Request["id"], out pkid))
{
//show
bol.Article bo = new dal.ArticleDal().GetBo(pkid);
if (bo != null)
{
//附件是图片
if ("jpg|jpeg|jpe｜gif".Contains(bo.FileExtName.ToLower()))
ExportImage(bo);//ExportDownload(bo);
else //附件是二进制
ExportDownload(bo);
}
}
}
}
}

private void ExportImage(bol.Article bo)
{
MemoryStream stream = new MemoryStream();
stream.Write(bo.AttachmentFile, 0, bo.AttachmentFile.Length);
Bitmap bitmap = new Bitmap(stream);

string content_type = "image/jpeg";          //默认为jpg格式
ImageFormat img_format = ImageFormat.Jpeg;   //默认为jpg格式
if (bo.FileExtName.ToLower().CompareTo("gif") == 0)
{
content_type = "image/gif";
img_format = ImageFormat.Gif;
}
else if ("jpg|jpeg|jpe".Contains(bo.FileExtName.ToLower()))
{
content_type = "image/jpeg";
img_format = ImageFormat.Jpeg;
}

Response.ContentType = content_type;
bitmap.Save(Response.OutputStream, img_format);
}
private void ExportDownload(bol.Article bo)
{
string fileName = string.Format("attch_{0}.{1}", bo.Pkid, bo.FileExtName); //客户端保存的文件名

Response.Clear();
Response.Buffer = true;
Response.Charset = "utf-8";
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
Response.ContentType = "application/octet-stream";
Page.EnableViewState = false;
Response.BinaryWrite(bo.AttachmentFile);
}
//
}
}

（3）、展示页：

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using WebSqlImageFile.bol;
using WebSqlImageFile.dal;

namespace WebSqlImageFile
{
public partial class Show : System.Web.UI.Page
{
protected int pkid = 0;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Request["id"] != null)
{
if (Int32.TryParse(Request["id"], out pkid))
{
//show
bol.Article bo = new dal.ArticleDal().GetBo(pkid);
if (bo != null)
{
lblPkid.Text = bo.Pkid.ToString();
lblTitle.Text = bo.ArticleTitle;
if ("jpg|jpeg|jpe｜gif".Contains(bo.FileExtName.ToLower()))
{
//img
li_img.Visible = true;
}
li_download.Visible = true;
}
}
}
}
}
//
}
}

（4）、列表页

<asp:Repeater ID="rp_list" runat="server">
<HeaderTemplate>
<table border="0" cellpadding="0" cellspacing="0">
<col style="width:240px; text-align:center;" />
<col style="width:80px; text-align:center;" />
<col style="width:80px; text-align:center;" />
<col style="width:80px; text-align:center;" />
<tr>
<th>标题</th>
<th>内码</th>
<th>扩展名</th>
<th>下载</th>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td><a href="Show.aspx?id=<%#((WebSqlImageFile.bol.Article)GetDataItem()).Pkid%>"><%#((WebSqlImageFile.bol.Article)GetDataItem()).ArticleTitle%> </a>   </td>
<td>[ <%#((WebSqlImageFile.bol.Article)GetDataItem()).Pkid%> ]   </td>
<td>[ <%#((WebSqlImageFile.bol.Article)GetDataItem()).FileExtName%> ]   </td>
<td><a href="AttachF.aspx?id=<%#((WebSqlImageFile.bol.Article)GetDataItem()).Pkid%>" target="download">下载</a></td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using WebSqlImageFile.bol;
using WebSqlImageFile.dal;

namespace WebSqlImageFile
{
public partial class List : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
List<bol.Article> list = new dal.ArticleDal().GetList();
rp_list.DataSource = list;
rp_list.DataBind();
}
}
//
}
}

6、小结：

（1）、从上传控件到byte数组：

int len = upload_file.ContentLength; //读上传文件,上传文件字节大小
bo.AttachmentFile = new byte[len]; //读上传文件,初始化一个byte数组,长度为上传文件字节大小
upload_file.InputStream.Read(bo.AttachmentFile, 0, len); //读上传文件,上传文件.输入流.读(字节数组,从0开始,长度为文件大小)

（2）、从byte数组插入到数据库Image类型的字段里：

SqlParameter para_AttachmentFile = new SqlParameter("@AttachmentFile", SqlDbType.Image); //参数类型为Image
para_AttachmentFile.Value = bo.AttachmentFile;
paras.Add(para_AttachmentFile);

（3）、从数据库Image类型的字段读出到byte数组：
bo.AttachmentFile = (byte[])objReader.GetValue(2);

（4）、从byte数组输出到aspx页面：

（4.1）提供下载：

private void ExportDownload(bol.Article bo)
{
string fileName = string.Format("attch_{0}.{1}", bo.Pkid, bo.FileExtName); //客户端保存的文件名

Response.Clear();
Response.Buffer = true;
Response.Charset = "utf-8";
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
Response.ContentType = "application/octet-stream";
Page.EnableViewState = false;
Response.BinaryWrite(bo.AttachmentFile);
}

（4.2）图片输出显示：

private void ExportImage(bol.Article bo)
{
MemoryStream stream = new MemoryStream();
stream.Write(bo.AttachmentFile, 0, bo.AttachmentFile.Length);
Bitmap bitmap = new Bitmap(stream);

string content_type = "image/jpeg"; //默认为jpg格式
ImageFormat img_format = ImageFormat.Jpeg; //默认为jpg格式
if (bo.FileExtName.ToLower().CompareTo("gif") == 0)
{
content_type = "image/gif";
img_format = ImageFormat.Gif;
}
else if ("jpg|jpeg|jpe".Contains(bo.FileExtName.ToLower()))
{
content_type = "image/jpeg";
img_format = ImageFormat.Jpeg;
}

Response.ContentType = content_type;
bitmap.Save(Response.OutputStream, img_format);
}